This application relates to wireless communication systems and techniques.
Wireless communication systems use electromagnetic radio waves to provide communication with and between mobile communication devices known as access terminals (ATs), such as mobile phones and portable computers equipped with wireless communication ports. Different types of wireless communication systems have been developed to provide different wireless communication applications. A wireless wide area network (WWAN), for example, may be designed to provide both voice and data services for mobile communication devices in a large geographical area, e.g., a nationwide network. One example of such a WWAN is a code division multiple access (CDMA) communication system that includes a regular voice or data call handling mechanism and a packet data handling mechanism for handling data packet services. The regular voice or data call handling mechanism includes base transceiver stations (BTSs) distributed in spatially divided cells and a network of base station controllers (BSCs) each connected to control multiple BTSs. A mobile switching center (MSC) is coupled between BSCs and a carrier public switched telephone network (PSTN) to handle the regular voice or data calls. Under the CDMA2000 standards, the packet data handling mechanism in a CDMA WWAN may include packet control function (PCF) modules and a packet data service node (PDSN) that are coupled between a BSC and the packet data network for transmitting the data packets. The packet data network may be configured to operate based on a proper packet data protocol, such as a carrier network based on the Internet Protocol (IP).
Different from the above CDMA WWAN or other WWANs, a wireless local area network (WLAN) is a wireless network that covers a small geographic area to provide packet data services for mobile communication devices. The WLAN can be better configured and optimized than a WWAN to provide faster and reliable data links for mobile users. Currently, the IEEE 802.11 standards have been widely adopted as one of the communication protocols for WLANs. Many high-speed WLAN services are usually provided locally in selected buildings or limited local areas called “hot spots” or “hot zones.”